352 QUICKSILVEK DEPOSITS OF THE rACIFIG SLOPE. 



association seems to point to the supposition that these metals are often 

 derived from the same source. It is therefore much more probable that the 

 silver, gold, and zinc also were derived from the granite at Steamboat than 

 that they came from the unknown regions beneath it or from some mass of 

 lava crossing it. As for the quicksilver, I am not aware that it has ever 

 been detected as a constituent of a massive rock ; but it is found at very 

 man}^ points the world over in association with gold, copper, arsenic, and 

 antimonj^, or some of them. All the circumstances at Steamboat seem to 

 point to the granite as its probable source, and, so far as I know, nothing 

 suggests a different origin. 



Conclusions — As Messrs. J. A. Phillips' and Laur'-' have pointed out. Steam- 

 boat affords instances of the formation of true fissure veins by hot springs 

 at the present day. While it is quite probable that some veins are formed 

 in a different maimer, it is substantially certain that many deposits have 

 been generated in this way. The composition of the waters, witli special 

 experiments devised for the pui'pose, also leads to definite conclusions con- 

 cerning the soluble compounds of the metals contained in the waters, as will 

 be shown in Cliapter XV. Steamboat Springs, too, affords a striking illus- 

 tration of lateral secretion. This term is sometimes limited to segregations 

 affected by cold solutions, but quite improperl}^, for the extraction and dep- 

 osition of ore from the rocks adjoining fissures by hot solutions are just as 

 much lateral secretion as if the prevailing temperature were low. The term 

 is used by von Cotta without any limitation as to temperature. As it has 

 been emj)loyed by Mr. S. F. Emmons and m}self also, a limitation as to 

 temperature has never been implied. 



Comparison with the comstock. — Tlicro aro notcwortliy similarities and differ- 

 ences between the deposits of Steamboat and of the Comstock lode. At 

 Steandjoat gold is })resent in much larger quantities than silver, as it is in 

 all the deposits of the gold belt of California. At the Comstock the pro- 

 portion of gold to silver by weight is only about 1 to 20. At Steamboat 

 arsenic and antimony, lead, copper, and mercury are the most abundant 

 metals, while on the Comstock mercury is not found at all and the j^i'evail- 

 ing ore is auriferous ar<jentite. As I showed in niv memoir on the Com- 



Ore Deposits, 1884. -Annales des iiiiues, vol. o, 1803, p. 423. 



